Question

Найдите периметр треугольника ABC, если A(-1; 2), B(2; 6), С(5; 2).​

Answer 1

$AB = \sqrt{(2-(-1)^2 + (6-2)^2} = \sqrt{9+16} = \sqrt{25} =5\\\\ BC = \sqrt{(5-2)^2+(2-6)^2} = \sqrt{9+16} =\sqrt{25} =5\\ \\ AC = \sqrt{(5-(-1)^2+(2-2)^2}= \sqrt{36} = 6\\ \\ P=5+5+6=16$